Seattle Grace/Mercy West is about to meet another one of Derek Shepherd's sisters. According to TVLine, Grey's Anatomy has cast Neve Campbell as one of Derek's four sisters for multiple episodes in season 9.

Of Derek's four sisters, we've already met two: neurosurgeon Amelia (now on Private Practice) and OB/GYN Nancy (played by Embeth Davidtz in season 3). It's unknown if Campbell will play Kathleen the psychiatrist or a fourth, unnamed and unknown sister.

My money's on the shrink, especially since Derek is going through a hard time this season as his severe hand injuries may prevent him from returning to his career as a surgeon.

Campbell is best known for her work on Party of Five as Julia Salinger and for starring in the Scream movies. More recently she starred in a new Titanic miniseries on Encore and on NBC's failed drama The Philanthropist.

Sadly Derek doesn't have any brothers, otherwise it would be a great opportunity to have a Party of Five reunion with Matthew Fox guest starring as Jack Shepherd, a prominent spinal surgeon who knows a thing or two about surviving a plane crash.

Campbell is scheduled to appear in at least two episodes of Grey's Anatomy.